If a shortage in worldwide supplies of fissionable uranium arose, it would be possible to use other fissionable nuclei. Plutonium, one such fuel, can be made in “breeder” reactors that manufacture more fuel than they consume. The sequence of reactions by which plutonium is made is as follows:
(a) A ²³⁸U nucleus undergoes an (n, γ) reaction to produce ²³⁹U.
(b) ²³⁹U decays by β emission (t_½ = 23.5 min) to give an isotope of neptunium.
(c) This neptunium isotope decays by β emission to give a plutonium isotope.
(d) The plutonium isotope is fissionable. On collision of one of these plutonium isotopes with a neutron, fission occurs, with at least two neutrons and two other nuclei as products. Write an equation for each of the nuclear reactions.